Dispensing devices for dispensing caulk and related compounds commonly employ a dispensing tip having an orifice which is formed or cut at an angle. This way, the angled edge of the dispensing tip can be used as a spatula for spreading and/or infusing the compound as it is being dispensed. This is best accomplished when the dispensing gun is held at an angle in order to keep the tip flush against the caulking surface. Unfortunately, unless one is caulking a straight line, it becomes awkward to maneuver the gun past curves and around corners.
For this reason, some dispensing guns are now equipped with rotatable barrels. One need only rotate the barrel while navigating corners in order to keep the dispensing tip flush against the caulking surface. The rotatable barrel makes it possible to apply a uniform and continuous bead of caulk even around corners.
Notwithstanding the great advantage, the rotatable barrel engenders one inherent inconvenience. It is necessary to keep a hand on the barrel to prevent it from rotating whenever rotation is not desired. This requirement prevents one-handed operation of the dispensing gun. The operator no longer has a free hand to maintain balance, clean the caulking path, smooth or remove excess caulk, or any of the numerous other tasks which could otherwise be performed during caulking.
For this reason, a number of barrel rotation locks have been developed to lock the barrel in position when rotation is no longer desired. In the simplest form, these barrel rotation locks take the form of threaded collars on the barrel which may be tightened to increase resistance to rotation. However, the collars generally defeat the purpose of the rotatable barrel. In order to lock or unlock the barrel, the dispensing gun must first be withdrawn from the work surface, and the operator must then turn the collar with his/her free hand. Consequently, the line of caulk is broken.
Since it is often of paramount importance to maintain a smooth and continuous line of caulk, more elaborate barrel rotation locks have been developed which partially solve the above-described problem. For example, Miyata U.S. Pat. No. 4,669,636 discloses a cartridge-type dispensing gun with a rotatable barrel and lock. The barrel of the gun is connected to the housing by a joint assembly which incorporates a lock for maintaining the barrel in one of a plurality of angular positions about its axis. The lock operates by a retractable ratchet spring which engages the barrel by one of a plurality of notches, thereby latching the barrel in position. The ratchet spring may be operated without removing the gun from the work surface. Hence, the barrel can be rotated while maintaining a continuous bead of caulk. However, the Miyata barrel rotation lock is exceedingly complex and costly to produce. It requires intricate parts and is prone to failure. Moreover, the barrel can be locked only at incremental angular positions, and the additional force required to override each incremental position is sufficient to interrupt or distort the line of caulk.